# This
require 'activesupport'

Object.class_eval do
  def self.has_behavior(behavior, options={})
    options.reverse_merge!({:from => name.underscore})

    require "#{options[:from]}/#{behavior}"
    mod = "#{options[:from].camelize}::#{behavior.to_s.camelize}".constantize

    include mod::InstanceMethods if defined?(mod::InstanceMethods)
    extend mod::ClassMethods if defined?(mod::ClassMethods)
    mod.initialize(self) if mod.respond_to?(:initialize)
  end
end

# Or in Rails
ActiveRecord::Base.class_eval do

  def self.has_behavior(behavior, options={})
    options.reverse_merge!({:from => name.underscore})

    require "#{options[:from]}/#{behavior}"
    mod = "#{options[:from].camelize}::#{behavior.to_s.camelize}".constantize

    include mod::InstanceMethods if defined?(mod::InstanceMethods)
    extend mod::ClassMethods if defined?(mod::ClassMethods)
    mod.initialize(self) if mod.respond_to?(:initialize)
  end

end

# With
module SharedBehaviors::Authenticated
  module InstanceMethods
    # Instance methods
  end

  module ClassMethods
    # Class methods
  end

  def initialize(klass)
    klass.class_eval do
      # do stuff
    end

    klass.send(:foo)
  end
end

# Or with
module User::Authenticated
  module InstanceMethods
    # Instance methods
  end

  module ClassMethods
    # Class methods
  end

  def initialize(klass)
    klass.class_eval do
      # do stuff
    end

    klass.send(:foo)
  end
end

# Will:
# 1. require 'shared_behaviors/authenticated'
# 2. Get the module SharedBehaviors::Authenticated
# 3. include SharedBehaviors::Authenticated::InstanceMethods if SharedBehaviors::Authenticated has InstanceMethods
# 4. extend SharedBehaviors::Authenticated::ClassMethods if SharedBehaviors::Authenticated has ClassMethods
# 5. call SharedBehaviors::Authenticated.initialize(User)

class User < ActiveRecord::Base
  has_behavior :authenticated, :from => :shared_behaviors
end

# Will:
# 1. require 'user/authenticated'
# 2. Get the module User::Authenticated
# 3. include User::Authenticated::InstanceMethods if User::Authenticated has InstanceMethods
# 4. extend User::Authenticated::ClassMethods if User::Authenticated has ClassMethods
# 5. call User::Authenticated.initialize(User)

class User < ActiveRecord::Base
  has_behavior :authenticated
end